Sprinkler tuning

Getting brown spots in the front yard. Looks water based. When I fired up the sprinklers to look at the distribution, it looked like two of the four were generating a short radius mist, and definitely not throwing water across the yard. On closer examination, appears the sprinkler heads are spinning very fast. I put my thumb against one to slow it down, and it resumed a pattern similar to the other two on the circuit, throwing water considerably further.

I have no knowledge of lawn maintenance or sprinkler systems, so do not worry about offending my intelligence in these matters, because I have none. What I know is that all four sprinkler heads are on the same circuit / pipe, and basically align with the four corners of my small square front yard, about 12 x 12 or so. Appears the first and last are rotating at appropriate speed, and the two in the middle are hauling balls. I am assuming the head rotation is as a result of water pressure. Any idea how to adjust these things?

Thanks for any help or thoughts!

JohnnyEgo

I would just replace the heads and be done in 20 min. They probably are stripped, it's happens over time. They screw off and are not very expensive.

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Originally Posted by Mazin

I would just replace the heads and be done in 20 min. They probably are stripped, it's happens over time. They screw off and are not very expensive.

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Yep. Most likely 1/2 inch. Dig them out and unscrew it. Try not to get dirt inside the riser.

Yep, replacement as mentioned.
When you dig them up, don't be lazy, dig around them enough to prevent dirt falling back into the supply line below. If you don't keep dirt out, the new head will clog up the screens inside as soon as you turn the water back on.
Also, test the new heads before re-burying them. It is no fun having to dig them back up due to a leak or clogging due to dirt getting in the line.

ask me how I know.........[facepalm]

Slow down there Bucky on the replacement. Are your zone valves adjustable for flow? If it has a knob (not the small bleeder) on top of the diaphragm bonnet it is probably a flow control.
Most people don't realize it but 90% of residential systems are wide open as far as flow goes. This causes the water to atomize into a mist instead of laying down a nice even stream. Depending on the head it may be adjustable for flow at the head.

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Originally Posted by BPTactical

Slow down there Bucky on the replacement. Are your zone valves adjustable for flow? If it has a knob (not the small bleeder) on top of the diaphragm bonnet it is probably a flow control.
Most people don't realize it but 90% of residential systems are wide open as far as flow goes. This causes the water to atomize into a mist instead of laying down a nice even stream. Depending on the head it may be adjustable for flow at the head.

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First & last in the zone are working fine according to the OP, these are the highest and lowest pressure areas respectively, so it wouldn't be the valve pressure.

Depends on the rotor heads you have. Many have a set screw for metering flow. Just YouTube "adjust (brand) sprinkler"

You guys have given me some good advice and leads for where to go next. I am heading out on business for a few days, but I plan to resolve this one way or another when I get back. I'll post up whatever I end up doing.

The sprinklers are Rainbird something-or-others, and knowing my builder, probably the bottom of the line. Thanks everyone for your help!

Check the heads as well for filter screens, clean or replace as needed.

If you want a affordable sprinkler guy, very, VERY good at it PM me.